Merocyanine dyes containing a 2-thiohydantoin nucleus and preparation thereof



United States Patent NIEROCYANINE DYES CONTAINING A Z-THIO- HYDANTOINNUCLEUS AND PREPARATION THEREOF No Drawing. Application August 3, 1953,

Serial No. 372,181

7 Claims. (Cl. 260-2404) This invention relates to merocyanine dyescontaining a 2-thiohydantoin nucleus and to methods for preparing them.More particularly, this invention relates to merocyanine dyes containinga 2-thiohydantoin nucleus containing and acyl substitutent, and tomethods for preparing them.

Merocyanine dyes containing a 2-thiohydantoin nucleus have long beenknown. Some of these dyes have been found to be quite useful inincreasing the sensitivity of photographic silver halide emulsions.

I have now found an entirely new class of merocyanine dyes which areuseful as sensitizers for photographic silver halide emulsions.

It is, accordingly, an object of my invention to provide'a new class ofmerocyanine dyes. A further object is to provide methods for preparingthese new dyes. Still another object is to provide photographic silverhalide emulsions sensitized with these new dyes, and methods forpreparing these emulsions. Other objects will become apparent from aconsideration of the following description and examples.

According to my invention, I provide new. merocyanine dyes representedby the following general formula:

wherein R represents an alkyl group, such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, n-amyl, n-octyl, beta-hydroxyethyl,beta-chloroethyl, beta-acetoxyethyl, etc. groups, (especially alkylgroups of the formula CmH21n+1 wherein m represents a positive integerof from 1 to 8), R1 represents an alkyl group, such as the alkyl groupsdefined by R above, as well as cycloalkyl groups, e. g. cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl (especially cycloalkyl groupscontaining from 3 to 6 carbon atoms in the cycloalkyl ring), or aralkylgroups, e. g. benzyl, beta-phenylethyl, etc., n represents a positiveinteger of from 1 to 2, d represents a positive integer of from 1 to 3,R represents an acyl group, such as acetyl, propionyl, butyryl,isobutyryl, benzoyl, etc., and Z represents the non-metallic atomsnecessary to complete a heterocyclic nucleus containing from 5 to 6atoms in the heterocyclic ring, such as those selected from the groupconsisting of those of the thiazole series (e. g. thiazole,4-methylthiazole, 4-phenylthiazole, S-methylthiazole, 5-phenylthiazole,4,5-dimethy1thiazole, 4,5-diphenylthiazole, 4-(2-thienyl) thiazole,etc.), those of the benzothiazole series (e. g. benzothiazole,4-chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole,7-chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole,'6-methylbenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole,4-phenylbenzothiazole, S-phenylbenzothiazole, 4-methoxybenzothiazole,S-methoxybenzothiazole, 6-methoxybenzothiazo1e, 5-iodobenzothiazole,6-iodobenzothiazole, 4-ethoxybenzothiazole, S-ethoxybenzothiazole,tetrahydrobenzothiazole,

2,719,152 Patented Sept. 27, 1955 ice 5,6-dimethoxybenzothiazole, 5,6dioxymethylenebenzothiazole, S-hydroxybenzothiazole6-hydroxybenzothiazole, etc.), those of the naphthothiazole series (e.g. alpha-naphthothiazole, beta-naphthothiazole,S-methoxybeta-naphthothiazole, 5-ethoxy-beta-naphthothiazole, 8-

. methoxy-alpha-naphthothiazole, 7-methoxy alpha-naphthothiazole, etc.),those of the thionaphtheno-7',6',4,5-

' azole,

thiazole series (e. g. 4-methoxythionaphtheno-7,6',4,5- thiazole, etc.),those'of the oxazole series (e. g. 4-methyloxazole, S-methyloxazole,4-pheny1oxazole, 4,5-diphenyloxazole, 4-ethyloxazole,4,5-dimethyloxazole, S-phenyloxazole, etc.), those of the benzoxazoleseries (e. g. benzoxazole, S-chlorobenzoxazole, S-methylbenzoxazole,5-phenylbenzoxazole, G-methylbenzoxazole, 5,6- dimethylbenzoxazole,4,6-dimethylbenzoxazole, S-methoxybenzoxazole, 5-ethoxybenzoxazole,S-chlorobenzox- 6-methoxybenzoxazole, S-hydroxybenzoxazole,6-hydroxybenzoxazole, etc.), those of the naphthoxazole series (e. g.alpha-naphthoxazole, beta-naphthoxazole, etc.), those of the selenazoleseries (e. g. 4-methylselenazole, 4-phenylselenazole, etc.), those ofthe benzoselenazole series (e. g. benzoselenazole,S-chlorobenzoselenazole, 5-methoxybenzoselenazole,S-hydroxybenzoselenazole, tetrahydrobenzoselenenazole, etc.), those ofthe naphthoselenazole series (e. g. alpha-naphthoselenazole,beta-naphthoselenazole, etc.), those of the thiazoline series (e. g.thiazoline, 4-methylthiazolone, etc.), those of the 2-quinoline series(e. g. quinoline, 3-methylquinoline, S-methylquinoline,7-methylquinoline, S-methylquinoline, 6-chloroquinoline,8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline,6-hydroxyquinoline,

8-hydroxyquinoline, etc.), those of the 4-quinoline series wherein R, Z,and n have the values set forth above, R2 represents a hydrogen atom, analkyl group (e. g. methyl, ethyl, etc.), or the acyl group of acarboxylic acid (e. g. acetyl, propionyl, etc.), R3 represents an arylgroup (e. g. phenyl, 0-, m-, and p-tolyl, etc.), or R2 and R3 togetherrepresent the non-metallic atoms necessary to complete a heterocyclicnucleus (e. g. a piperidyl, morpholinyl, etc. nucleus), p represents apositive integer from 1 to 2, and X1 represents an acid radical, e. g.Cl, Br-, I, CzH5SO4", p-CH3CsH4SOr, SCN, etc., with a 2-thiohydantoincompound selected from those represented by the following generalformula:

I HaC 5 alkylanilines, such as N,N-diethylaniline, etc., heterocyclictertiary amines, such as pyridine, quinoline, N-alkyl piperidines, etc.,alkali metal alcoholates, such as sodium ethylate. The condensations canalso be carried out in the presence of an inert diluent, such asmethanol, ethanol, n-propanol, isopropanol, n-butanol, diethyl ether,acetone, 1,4-dioxane, etc.

The merocyanine dyes of Formula I above where d is 1 can be prepared bycondensing a cyclammonium quaternary salt selected from thoserepresented by the following general formula:

wherein R. Z, X1, and n have the values set forth above, and R4represents an alkyl group, such as methyl, ethyl, etc., or an arylgroup, such as phenyl, o-, m-, and p-tolyl, etc., with a Z-thiohydantoinselected from those represented by Formula III above. The condensationscan advantageously be carried out in the presence of a basic condensingagent, such as the trialkylamines (e. g. triethylamine,tri-n-butylamine, etc.), dialkylanilines (e. g. N,N-dimethyl-, andN,N-diethylaniline, etc.), heterocyclic tertiary amines (e. g. pyridine,quinoline, N-alkylpiperidincs, etc.), alkali metal alcoholates (e. g.sodium methylate, sodium ethylate, etc.), etc. The condensations canalso be carried out in the presence of an inert diluent, such asmethanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol,diethyl ether, acetone, 1,4- dioxane, etc.

The following examples will serve to illustrate more fully the mannerwhereby I practice my invention.

Example 1.-1-acetyl-5-[ (3-2thylbenzoxazolin-Z-ylidene) ethylidene]-3-methyl-2-thiohydantoin 4.0 g. of 1-acetyl-3-methyl-2-thiohydantoin,4.3 g. of 2-beta-acetanilidovinylbenzoxazole ethiodide and 1.01 g. oftriethylamine in 15 cc. of ethanol were refluxed for minutes on thesteam bath. After chilling and filtering, the dye was recrystallizedfrom pyridine-methanol as chocolate-brown leaflets, M. P. 204 C.

Example 2.1-acetyl-5-[ (3-ethylbenzoxaz0lin-2-yliaene) ethylidene]-3-ethyl-2-thi0hydant0in 4.0 g. of 1-acetyl-3-ethyl-2-thiohydantoin,4.34 g. of 2-beta-acetanilidovinylbenzoxazole ethiodide with 1.01 g. oftriethylamine in cc. of ethanol were refluxed together for 10 minutes onthe steam bath. After chilling and filtering, the dye was recrystallizedfrom pyridine ether as a black-red powder, M. P. 264 C. dec.

Example 3.--1-acetyl-5- (3-ethylbenzoxazolin-Z-ylidene) ethylidene]-3-n-0cty Z-Z-thiohya'antoin 2.0 g. of1-acetyl-3-n-octyl-2-thiohydantoin, 2.17 g. of2-beta-acetanilidovinylbenzoxazole ethiodide with 0.5 g. oftriethylamine in 10 cc. of ethanol were refluxed together for 10 minuteson the steam bath. After chilling and filtering, the dye wasrecrystallized from ethanol as an orange sponge, M. P. 176 C.

Example 4 .1 acetyl-3-benzyl-5-[ (3-ethylbenz0xaz0lin-2-ylidene)ethylidene] -2-thiohydant0in 2.0 g. ofl-acetyl-3-benzyl-2-thiohydantoin, 2.17 g. of2-5-acetanilidovinylbenzoxazole ethiodide with 0.5 g. of triethylaminein 10 cc. of ethanol were refluxed together for 10 minutes on the steambath. After chilling and filtering, the dye was recrystallized frombenzene-petroleum ether as orange needles, M. P. 220 C.

Example 5 .1 -acetyl-3-carboxymethyl-S (3 -ethylbenzoxazolin-Z-ylideneethylidene] -2-thi0hydant0in 2.0 g. of1-acetyl-3-carhoxymethyl-2-thiohydantoin, 2.17 g. of2-fl-acetanilidovinylbenzoxazole ethiodide, 0.5 g. of triethylamine, and10 cc. of ethanol were heated together for 10 minutes on the steam bath.The dye, after chilling and filtering, was recrystallized fromethanol-ether as an orange-brown powder, M. P. 243 C.

Example 6 .-1 -acetyl-3 -ethyl-5 (3 -ethylbenzo1hiaz0lin-2-ylidene)ethylidene] 2-thiohydant0in O=(")-NCzH5 C=CHCH=C S N N (I; O:C -O H;

4.0 g. of l-acetyl-3-ethyl-2-thiohydantoin, 4.5 g. of

Z-fi-acetanilidovinylbenzothiazole ethiodide with 1.0 g. oftriethylamine in 15 cc. of ethanol were refluxed on the steam bath for10 minutes. After chilling and filtering, the dye was recrystallizedfrom benzene-petroleum ether as dark blue prisms, M. P. 201 C.

Example 7.1-acetyl-5-[ (3-ethylbenz0thiaz0lin-2- ylidene) ethylidene]-3-n-octyl-2-thiohydantoin 2.0 g. of 1-acetyl-3-n-octyl-2-thiohydantoin,2.25 g. of Z- S-acetanilidovinylbenzothiazole ethiodide with 0.5 g. oftriethylamine in 10 cc. of ethanol were refluxed on the steam bath for10 minutes. After chilling and filtering, the dye was recrystallizedfrom benzene-petroleum ether as orange flakes, M. P. 180 C.

Example 8.1-acetyl-3-benzyl-5-[ (3-ethylbenzothiaz0lin- 2-ylidene)ethylidene] -2-thi0hydantoin 2.0 g. of 1-acetyl 2-benzyl 2thiohydantoin, 2.25 g. of Z-fi-acetanilidovinylbenzothiazole ethiodidewith 0.5 g. of triethylamine in cc. of ethanol were refluxed'on thesteam bath for 10 minutes. After chilling and filtering, the dye wasrecrystallized from benzene-petroleum ether as maroon needles withbronze reflex, M. P. 210 C.

Example 9.1-acetyl-5-[ 3 -ethylbenzothiazolin-2- ylidene) ethylidene]-3-cyclohexyl-2-thiohydantoin 2.0 g. of1-acetyl-3-eyclohexyl-2-thiohydantoin, 2.25 g. of2-B-acetanilidovinylbenzothiazole ethiodide with0.5 g. of triethylaminein 10 cc. of ethanol were refluxed on the steam bath for 10 minutes.After chilling and filtering, the dye was recrystallized frombenzene-petroleum ether as glossy crimson needles, M. P. 221 C. i i

Example 10.1-acetyl-3-carb0xymelhyl-5-[(3-ethylbenzothiazolin-Z-ylidene) ethylidene] -2-thi0hydant0in 2.0 g. ofl-acetyl-3-carboxymethyl-Z-thiohydantoin, 2.25 g. of2-[3-acetanilidovinylbenzothiazole ethiodide with 0.5 g. oftriethylamine in 10 cc. of ethanol were refluxed on the steam bath for10 minutes. After chilling and filtering, the dye wasrecrystallized'from benzene-petroleum ether as green prisms, M. P. 248C.

2.0 g. of 1-acetyl-3-ethyl-2-thiohydantoin, 2.01 g. of2-[3-acetanilidovinylthiazoline ethiodidewith 0.5 g. of triethylamine in10 cc. of ethanol were refluxed for '10 minutes. After chilling andfiltering, the dye was, recrystallized from methanol with anethylacetate-petroleum ether mixture as glistening orange needles, M. P.179 C.

Example 12.--] acetyl-S-ethyl-S[4-(3-ethylbenzothiaz0-lin-2-ylidene)but-2en-1 -ylidenel-2-thi0hydantoin 2.0 g. ofl-acetyl-3-ethyl-2-thiohydantoin, 2.38 g. of 2-(6-acetanilido 1,3butadienyl)benzothiazole ethiodide with 0.5 g. of triethylamine in 10cc. of ethanol were refluxed for 10 minutes. After chilling andfiltering, the dye was recrystallized from methanol with anethylacetatepetroleum ether mixture as indigo needles, M. P. 155 C.

6 Example 13.-I-acetyl-3-ethyl-5- (3-ethylbenz0selenaz0- lin-Z-ylideneethylidene] -2-thiohydant0in 2.0 g. of 1-acetyl-3-ethyl-2-thiohydantoin,2.5 g. of 213- acetanilidovinylbenzoselenazole ethiodide with 0.5 g. oftriethylamine in 10 cc. of ethanol were refluxed for 10 minutes. Afterchilling and filtering, the dye was recrystallized frombenzene-petroleum ether as an indigo powder, M. P. 243 C.

Example 14.-] acetyl-3-ethyl-5-[(3-ethylnaphtho-1:2-4:5-thiaz0lin-2-ylidene)ethylidene]-2-thiohydant0in 2.0 g. of1-acetyl-3-ethyl-2-thiohydantoin, 2.5 g. of 2-5-acetanilidovinylnaphtho-l 2'-4 S-thiazole ethiodide with 0.5 g. oftriethylamine in 10 cc. of ethanol were refluxed for 10 minutes. 'Afterchilling and filtering, the dye was recrystallized frombenzene-petroleum ether as maroon needles, M. P. 210 C.

'Example 15.--] acetyl-3-ethyl-5-[(3-ethyl-4,5-diphenyloxazolin-Z-ylidene) ethylidene] -2-thiohydant0inExample 16.---] acetyl-3-ethyl-5-[(3-ethyl-4,5-diphenyl- 2.0 g. of1-acetyl-3-ethyl-2-thiohydantoin, 2.77 g. of 2-5-anilinovinyl-4,S-diphenylthiazole etho-p-toluenesulfonate, 0.5 g. ofacetic anhydride with 1.01 g. of triethylamine in 12 cc. of ethanol-wererefluxedfor 10minutes on the steam bath. After chilling and filtering,the dye was recrystallized from benzene-petroleum etheras glisteninground leaflets, M. P. 210 C. 1

Example 17.1 acetyl-3-ethyl-5- (I-ethyldihydroquino liri-Z-ylidene)ethylidene -2-thiohydant0in 2.0 g. of 1-acetyl-3-ethyl-2-thiohydantoin,2.22 g. of 2-fiacetanilidovinylquinoline ethiodide with 0.5 g. oftriethylamine in 10 cc. of ethanol were refluxed for 10 minutes on thesteam bath. After chilling and filtering, the dye was recrystallizedfrom pyridine-methanol as an indigo powder, M. P. 207 C.-

Example 18.] acetyl-3-ethyl-5-l (1 -ethyla'ihydr0quin0-line-4-ylidene)ethylidene] -2-thi0hydant0in O=(|l-NC2Hs OH--CH=C :5

I O=CCH3 2.0 g. of 1-acetyl-3-ethyl-2-thiohydantoin, 2.22 g. of 4-5-acetanilidovinylquinoline ethiodide with 0.5 g. of triethylamine in 10cc. of ethanol were refluxed for 10 minutes on the steam bath. Afterchilling and filtering, the dye was recrystallized frombenzene-petroleum ether as dark green needles, M. P. 184 C.

Example 19.1-acetyl-3-ethyl-5-(3-ethylbenzothiazolin-2- ylidene)-2-thiohydantoin Example 20.1-acetyl-3b enzyl- (3-ethylnaphth0-1':2'- 45 -0xazolin-2-ylidene) ethylidene] -2-thi0hydant0in 2.0 g. of3-benzyl-l-acetyl-2-thiohydantoin, 2.42 g. of 2 43-acetanilidovinlnaphtho 1':2-4:5 oxazole ethiodide with 0.7 cc. oftriethylamine in cc. of ethanol were heated for 10 minutes on the steambath. The dye was collected and recrystallized from pyridine-methanol asorange flakes, M. P. 320 C.

Example 21.-3-ethyl5-[(3-ethylthiazolidin 2 ylidene)ethylidene]-1-pr0pionyl-Z-thiohydantoin 3-ethyl-1 propionyl 2thiohydantoin, which resulted from the reaction described below inExample 29, 4.0 g. of 2-[3-acetanilidovinylthiazoline ethiodide and 1.4cc. of

triethylamine in cc. of ethanol were heated for 10min 8 utes on thesteam bath. The dye which crystallized on cooling was recrystallizedfrom benzene-petroleum ether as khaki needles, M. P. C.

Example 22.-3-ethyl-5-[ (3 -ethylbenzoxazolin-2-ylia'ene) ethylidene-I-propionyl-Z-thiohydantoin 3-ethyl-1-propionyl-2-thiohydantoin obtainedaccording to Example 29 below, 4.34 g. ofZ-B-acetanilidovinylbenzoxazole ethiodide with 1.4 cc. of triethylaminein 15 cc. of ethanol were refluxed 10 minutes on the steam bath. Oncooling, the .dye crystallized and it was recrystallized frombenzene-petroleum ether as red flakes with a blue reflex, M. P. C.

The Z-thiohydantoin compounds embraced by Formula III above canadvantageously be prepared by condensing together a compound selectedfrom those represented by the following general formula:

E n H Ri-N-CNCH:C 0 OH wherein R1 has the values given above togetherwith a carbocyclic anhydride selected from those represented by thefollowing general formula:

H e-C wherein R6 represents an alkyl group, e. g. methyl, ethyl, propyl,isopropyl, etc. or an aryl group, e. g. phenyl, o-, mand p-tolyl, etc.(cf. Harries and WeissAnn.- vol. 327 (1903), page 355; Brautlecht-J.Biol. Chem. v01. 10 (1911), page 139; and Johnson and Renfrewvol. 33(19l1) page 1977 and vol. 47 (1925), page 240.

The following examples will serve to illustrate the preparation of theintermediates represented by Formula III above.

Example -23.1-acetyl-3-methyl-2-thiohydantoin Q=C-NCH3 H2C =S N O= 0 Ha4.0 g. of N-carboxymethyl-N-methylthiourea and 15 cc. of aceticanhydride were heated for a quarter of an I hour on the steam bath andthe solvents were removed under reduced pressure. The resulting oil wasused in the above examples without further purification.

Example 24.1-acetyl-3-ethyl-2-thiohya'antoin N -O= JCHa Thisintermediate was prepared in the same manner as that of Example 23,using 4.0 g. of N-carboxymethyl-N'- ethylthiourea and acetic anhydride.

Example 25.1-acetyl-3-n-0ctyl-2-thiohydantoin O=CNCEH11( that of Example23 using N-carboxymethyl-N-benzyl thiourea and acetic anhydride.

Example 27 .1 -acetyl-3-cyclohexyl-2-thiohydant0in NCnHu H2O S N O=(ECH3 This intermediate was prepared in the same manner as that of Example23 using N-carboxymethyl-N'-cyclohexyl thiourea. I

Example 28.1-acetyl-3-carb0xymethyl-Z-thiohydantoin O=C-NC H20 0 OH H20:3 l 0=c0 Ha This intermediate was prepared in the same manner as thatof Example 23 using N,N'-dicarboxymethyl thiourea.

Example 29.3-ethyl-1-pr0pi0nyl-2-thiohydantoin O=CNO2H l H2O :S iO=CO2H5 2.0 g. of N-carboxymethyl-N'-ethylthiourea and cc. of propionicanhydride were heated for a quarter of an hour on the steam bath and theresidual solvents removed under reduced pressure. The resulting oil wasused directly to prepare the dyes of Examples 21 and 22 above.

In like manner, other acylated Z-thiohydantoin compounds can be preparedby using carboxylic anhydrides diflerent from those illustrated inExamples 23-29 above. The intermediates represented by Formula V abovecan advantageously be prepared by condensing together a compoundselected from those represented by the following general formula:

VII H H RS-C-N-CH2COOR wherein R represents an alkyl group, such asmethyl,

ethyl, etc., and R" represents a hydrogen atom or an 1 alkyl group, suchas methyl, ethyl, etc., with a primary amine selected from thoserepresented'by the following general formula:

VIII R1NH2 wherein R1 has the values set forth above, in the presence ofaqueous alkali, e. g. potassium hydroxide.

The following examples will serve to illustrate the manner whereby theintermediates of Formula V can be prepared.

Example 30.N-carb0xymethyl-N'-methylthiourea 10 was washed with coldwater, and recrystallized from at mixture of methanol and ethyl acetateby adding petroleum ether. It was obtained as colorless prisms, M. P.168 C.

Example 31 .N-carboxymethyl-N'-ethylthi0urea N-dithiocarbethoxyglycine(53.7 g.) and potassium hydroxide (16.8 g.) were dissolved in water (45cc.) and ethanol cc.). Ethylamine, 70% in aqueous solution (21 cc.), wasadded, and the whole refluxed for 24 hours. Two-thirds of the solventwas distilled off at reduced pressure, and the residual solution cooledand acidified with HCl. On scratching a solid separated. This was washedwith cold Water, and recrystallized from ethyl acetate containing alittle methanol, and petroleum ether, as colorless prisms, M. P. 170 C.

Example 32.--N-carb0xymethyl-N'-n-octylthioureaN-dithiocarbethoxyglycine (53.7 g.) and potassium hydroxide 16.8 g.)were dissolved in water (45 cc.) and ethanol (90 cc.). n-Octylamine (43g., 56 cc.) was added, and the whole refluxed for 24 hours. Two-thirdsof the solvent was distilled off at reduced pressure, and the residualsolution cooled and acidified with I-ICl. On scratching a solidseparated. This was washed with cold water, and was recrystallized fromethyl acetate by adding petroleum ether, as colorless waxy needles, M.P. C.

Example 33.N-benzyl-N'-carb0xymethylthioarea N-dithiocarbethoxyglycine(26.9 g.) and potassium hydroxide (8.4 g.) were dissolved in ethanol (70cc.), and benzylamine (16.5 g.) added. The solution was refluxed 24hours. Water (35 cc.) was added, and the solution acidified with HCl. Asolid precipitated. It was Washed with water, and recrystallized fromethyl acetate containing a little methanol, and petroleum ether, aswhite prisms, M. P. 189 C.

Example 34.N-carb0xymethyl-N'-cyclohexylthioureaN-dithiocarbethoxyglycine (26.9 g.) and potassium hydroxide (8.4 g.)were dissolved in ethanol (70 cc.) and cyclohexylamine (16 g., 19.5 cc.)added. The solution was refluxed 24 hours. Water (35 cc.) was added, andthe solution acidified with HCl. A solid precipitated. It was washedwith water, and recrystallized from ethyl acetate-petroleum ether ascolorless needles, M. P. C.

Example 35 .N,N '-dicarboxymethylthiourea N-dithiocarbethoxyglycine(17.9 g.) and potassium hydroxide (11.2 g.) were dissolved in water (15cc.) and ethanol (30 cc.). Glycine (7.5 g.) was added, and the solutionrefluxed 24 hours. Two-thirds of the solvent was removed, and theresidue acidified with HCl. The product which precipitated wasrecrystallized from ethyl acetate, containing a little methanol, andpetroleum ether, as colorless prisms, M. P. C. with decomposition.

I have found that my new dyes spectrally sensitize photographic silverhalide emulsions when incorporated therein. The dyes are especiallyuseful for extending the spectral sensitivity of the customarilyemployed gelatinosilver-chloride, gelatino-silver chlorobromide,gelatinosilver-bromide and gelatino-silver bromiodide developingoutemulsions. To prepare emulsions sensitized with one or more of my newdyes, it is only necessary to disperse the dye or dyes in the emulsions.The methods of incorporating dyes in emulsions are simple and are knownto those skilled in the art. In practice, it is convenient to add thedyes to the emulsions in the form of a solution in an appropriatesolvent. Methanol or acetone has proved satisfactory as a solvent formost of my new dyes. Where the dyes are quite insoluble in methylalcohol, a mixture of acetone and pyridine is advantageously employed asa solvent. The dyes are advantageously incorporated in the finished,Washed emulsions and should be uniformly distributed throughout theemulsions. The particular solvent used will, of course, depend on thesolubility properties of the particular dye.

The concentration of the dyes in the emulsions can vary widely, e. g.from to 100 mg. per liter of flowable emulsion. The concentration of thedyes will vary according to the type of emulsion and according to theeffect desired. The suitable and most economical concentration for anygiven emulsion will be apparent to those skilled in the art, upon makingthe ordinary tests and observations customarily used in the art ofemulsion making. To prepare a gelatino-silver-halide emulsion sensitizedwith one or more of my new dyes, the following procedure issatisfactory:

A quantity of dye is dissolved in methyl alcohol or acetone (or amixture of acetone and pyridine) and a volume of this solution, whichmay be diluted with water, containing from 5 to 100 mg. of dye, isslowly added to about 1000 cc. of gelatino-silver-halide emulsion, withstirring. Stirring is continued until the dye is thoroughly dispersed inthe emulsion.

With most of my dyes, from to mg. of dye per liter ofgelatino-silver-bromode or bromiodide emulsion (containing about 40 g.of silver halide) suflices to produce the maximum sensitizing effect.With the finer grain emulsions, somewhat larger concentration of dye maybe needed to produce the maximum sensitizing effect.

The above statements are only illustrative, as it will be apparent thatthe dyes can be incorporated in photographic emulsions by any of theother methods customarily employed in the art, e. g. by bathing a plateor film upon which an emulsion is coated in a solution of the dye in anappropriate solvent. However, bathing methods are ordinarily not to bepreferred. Emulsions sensitized with the dyes can be coated on suitablesupports, such as glass, cellulose derivative film, resin film or paperin the usual manner.

The following table summarizes the sensitizing data obtained for severalof the dyes obtained in the above examples.

SENSITIZING DATA Chlorobromide Iodobromlde Exam plo Peak Limits PeakLimits 11) 1 530 to 580 530 to 570 635 to 570 530 to 560 550 to 600 520to 570 530 to 580 530 to 570 530 to 570 530 to 560 580 480-620 575 to620 590 520-620 570 to 610 580 480-620 675 to 610 575 to 630 570 to 610610 480-670 570-610 to 650 530 to 570 530 to 580 560-640 520-680 580490-620 570 520-610 600 470-650 590 510-640 535 to 580 530 to 570 590470-640 580 to 620 530-630 480-71 570-620 to 670 580-700 610-680 550-720550 470-580 545 to 560 530 470-560 to 550 545 to 580 530 to 580Photographic silver halide emulsions, such as those listed above,containing the sensitizing dyes of my invention can also contain suchaddenda as chemical sensitizers, e. g. sulfur sensitizers (e. g. allylthiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), variousgold compounds (e. g. potassium chloroaurate, auric trichloride, etc.)(see U. S. Patents 2,540,085; 2,597,856 and 2,597,915), variouspalladium compounds, such as palladium chloride (U. S. 2,540,086),potassium chloropalladate (U. S. 2,598,079), etc., or mixtures of suchsensitizers; antifoggants, such as ammonium chloroplatinate (U. S.2,566,245), ammonium chloroplatinite (U. S. 2,566,263),

benz0triazole,- nitrobenzimidazole, S-nitroindazole, benzidine,mercaptans, etc. (see MeesThe Theory of the Photographic Process,MacMillan Pub., page 460), or mixtures thereof; hardeners, such asformaldehyde (U. S. 1,763,533), chrome alum (U. S. 1,763,533, glyoxal(U. S. 1,870,354), dibromacrolein (Br. 406,750), etc.; color couplers,such as those described in U. S. Patent 2,423,730, Spence and Carroll U.S. application 771,380, filed August 29, 1947, etc.; or mixtures of suchaddenda. Dispersing agents for color couplers, such as those set forthin U. S. Patents 2,322,027 and 2,304,940, can also be employed in theabove-described emulsions.

What I claim as my invention and desire secured by Letters Patent of theUnited States is:

1. A merocyanine dye selected from those represented by the followinggeneral formula:

wherein R represents an alkyl group of the formula CmH2m+1 wherein mrepresents a positive integer of from 1 to 8, R1 represents a memberselected from the group consisting of an alkyl group of the formulaCqH2q+1 wherein q represents a positive integer of from 1 to 8, acycloalkyl group containing from 3 to 6 carbon atoms in the cycloalkylring, and an aralkyl group containing from 7 to 8 carbon atoms, R5represents an acyl group selected from the group consisting of acetyl,propionyl, butyryl, isobutyryl, benzoyl, and toluoyl, n represents apositive integer of from 1 to 2, d represents a positive integer of from1 to 3 and Z represents the non-metallic atoms necessary to complete aheterocyclic nucleus containing from 5 to 6 atoms in the heterocyclicring.

2. The merocyanine dye represented by the following formula:

3. The merocyanine dye represented by the following formula:

4. The merocyanine dye represented by the following formula:

5. The merocyanine dye represented by the following formula:

6. The merocyanine dye represented by the following formula:

7. A method for making merocyanine dyes comprising condensing a2-thiohydantoin compound selected from those represented by thefollowing general formula:

to 8 carbon atoms, and R5 represents an acyl group selected from thegroup consisting of acetyl, propionyl, butyryl, isobutyryl, benzoyl, andtoluoyl, with a cyclammonium quaternary salt selected from those havingthe following general formula:

wherein R represents an alkyl group of the formula CmH2m+1 wherein mrepresents a positive integer of from 1 to 8, X1 represents an acidradical, n represents a positive integer of from 1 to 2, Z representsthe non-metallic atoms necessary to complete a heterocyclic nucleuscontaining from 5 to 6 atoms in the heterocyclic ring and D represents amember selected from the group consisting of an alkylmercapto group, anarylmercapto group, a p-arylaminovinyl group, and a6-arylamino-1,3-butadienyl group.

No references cited.

1. A MEROCYANINE DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWINGGENERAL FORMULA: